Thesis (M.Sc.)--College of William and Mary. / Vita. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1963. / Includes bibliography: leaves [39]-40.

A study was conducted at Yaquina Bay, Oregon, to determine the age-fecundity relationships in the striped seaperch Embiotoca lateralis. A questionnaire was sent to California, Oregon, and Washington to ascertain what regulations were in effect, and the value of the family Embiotocidae with regard to the sport and commercial harvest. The questionnaire revealed that no state maintained a systematic account of each species landed, and further life history data appeared desirable for sport and commercial species. Fish were collected from March 20 to August 21, 1960, with 140 females and 26 males being collected for analysis by hook and line or 125-foot experimental gill net. Scales were imprinted on cellulose acetate cards or mounted between glass slides, The catch was measured in centimeters of standard length and weighed in grams. From 123 females, 2, 654 embryos were obtained, and a maximum of 22 embryos per female was measured in millimeters of standard length. The estimated time of annulus formation in most scales was from March 15 to June 12. Second and third annuli were primarily laid down in March and April, with the probable peak of annulus formation for females of ages IV, V and VI in May. Length-frequencies were presented by age-class and sex. Eighty-one females of age-class III dominated the sample. Females of age-classes II and III attained greater average lengths than males. In age-class II, average weights for females were slightly greater than those for males. Both sexes generally mature for the first time in their third year of life. Length-weight, and length-number of embryos per female, for females of age-classes III-IV, were expressed by the regression equation Y[subscript c] = a+ b (X). High correlations for length-weight were ob- tained. Additional females were needed to evaluate that age when weights would digress. Females of age-class V produced the most embryos per unit increase in length; this rate declined in age-class VI. The largest number of embryos produced by an age class was 1, 431, in age-class III. The average number (in parentheses) of embryos produced per female of each age class, was: II ( 17); III (18); IV (21); V (30); VI (31) and VII (32). The most prolific female was seven years old and contained 45 embryos. Sixteen diminutive embryos were collected in 10 out of 128 mature females. Most older females were thought to have ovulated earlier than younger females, for their embryos were generally larger than embryos of younger females. However, embryos from younger females could reach the approximate mean size of embryos of older females, but at a later date. Birth of embryos began about June 12 and ended in late July. Embryos averaged about 50 mm in standard length at birth. Suggestions are given for management of the striped seaperch. / Graduation date: 1966

During 1980 and 1981 respectively, 2425 and 4028 yellow perch 150-359 mm were Floy-tagged from June through August at four sites in Indiana waters of Lake Michigan. Most of the 6453 perch were tagged from mid-June to early August and almost 90% were less than 210 mm.An overall recapture rate of 3.2% (204 fish) was obtained by April 1, 1982. Site recapture rates were positively related to the numbers of fish tagged. Slightly over 92% of all fish were tagged at sites M and K and 94.5% of all recaptures originated from these two sites. Second season recaptures accounted for 25.5% of all recaptures. Peak recapture rates occurred in July. Sources of recaptures were 67.6% from sport fishermen, 25.5% from commercial fishermen, and 6.9% from Indiana Department of Natural Resources, Ball State University trawl catches and other sources.Most recaptured perch were in the 150-229 mm length interval, but an apparent size selection by both commercial and sport gear existed towards 180-229 mm perch. The recapture of large numbers of 150-159 mm fish indicated survival of small perch was not an important factor influencing size selection. Information on sizes of fish recaptured by sex and age was insufficient for evaluation.Although straight line movements of up to 166 km occurred, most fish remained near the original tagging sites. Distances traveled were similar for fish from all tagging sites in 1980, 1981 and for second season recaptures. Over 76% of all fish were recaptured in Indiana waters and about 86% traveled less than 32.0 km from the original tagging sites. The majority (64%) of fish leaving Indiana waters were captured nearby at New Buffalo and Union Pier, Michigan. About 68% of all recaptures were received within 60 days of release. Even though considerable variability was evident in the distances traveled with time, no seasonal trends were observed for perch of various sizes.Simple regression analysis of data for combined years revealed only 27% of all variation in distance traveled by perch was accounted for by the time at large (days) prior to recapture. Multiple regression analysis revealed the time at large was more important than fish length in relation to distance traveled, accounting for 27.3% and 0.2% of the explained variability, respectively. Data including second season recaptures more accurately represented these relationships and indicated these variables were poorly related to distance traveled. Examination of residuals showed a dramatic and statistically undesirable increase in unexplained variability was associated with far ranging fish. Other factors should be considered in future multiple regression analyses.Indiana yellow perch stocks appear to be fairly discrete entities. The majority of fish tended to remain periods of at least one year.

Thesis (M.S.)--University of Toledo, 2008. / Typescript. "Submitted as partial fulfillments of the requirements for The Master of Science Degree in Biology (Ecology-track)." "A thesis entitled"--at head of title. Bibliography: leaves 19-23.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

Please read the abstract in the section 00front of this document / Thesis (PhD(Food Science))--University of Pretoria, 2005. / Food Science / unrestricted

This thesis was conducted to evaluate the potential of obtaining yellow perch eggs and fry by controlling the reproductive cycle of broodfish and the techniques used to rear the resulting fry. Chapter 1 is a review of literature pertaining to yellow perch culture and related topics. Chapter 2 is a study of yellow perch broodstock exposed to a 6-month, artificial photothermal cycle and injected with LHRHa and pimozide to induce spawning. The mean gonadosomatic index for manipulated females was 24.2% and the mean fertility of eggs from manipulated females was 26.5%. The fertilization rate was significantly greater among strip-spawned females than tank spawned females (p < 0.05). The time to ovulation after injection showed a negative correlation (r2 = 0.505) with the mean oocyte diameter of manipulated females. Chapter 3 is a study comparing the performance of larval yellow perch reared in a recirculating system fed only live rotifers (T1), in a recirculating system fed live rotifers and an artificial diet (T2) and in a greenwater system (T3). Survival was low in all treatments. The specific growth rate did not differ among treatments over the first 6 days. The percentage of fry with inflated swimbladders and absorbed yolksacs did not differ by day 6. While T3 larvae began ingesting food earlier than T1 and T2, the percentage of fry ingesting food did not differ among treatments by day 6 (p >0.1). The total percentage of skeletal deformities was greater in T3 than either T1 or T2 (p < 0.05) and may have been due to excessive handling of T3 larvae during hatch-out. Chapter 4 outlines the costs associated with a yellow perch hatchery designed around photothermally manipulated broodstock. This hatchery model produces four separate spawns annually, yielding 644,000 fingerlings year-1. Including start-up, fixed and variable costs, such a facility can produce 3" (76mm) fingerlings for $0.20 fingerling-1 for the first 5 years of operation, $0.16 fingerling-1 for the second 5 years and $0.06 fingerling-1 after 10 years. / Master of Science

Thesis (M.S.)--University of Wisconsin -- La Crosse, 2009. / Includes bibliographical references (leaves 44-46)

A main concern in fisheries science has been to identify an accurate index of fish abundance. An underlying paradigm in the science has been that the amount of effort (calculated in hours and standardized for boat size) spent fishing was the best variable to be used to account for the variation in catches. The use of the ratio, catch per unit of effort (cpue), assumes that variations in fish abundance are due to human-controlled processes above the ocean's surface. It does not account for variation due to oceanographic processes that affect fish behaviour and movement patterns below the ocean's surface. This study investigated the possibility that oceanographic factors such as temperature, salinity and depth could have effects on the variations observed in the apparent abundance of a demersal rockfish, Pacific Ocean Perch (Sebastes alutus. Gilbert). Simultaneous monitoring of physical variables and fish abundance estimation was achieved by attaching oceanographic equipment to the fishing gear of commercial vessels, monitoring the acoustic equipment and sampling the fish catch. It was found that Perch prefer a temperature range from 6.7 °C, down to at least 4.8 °C and that their movement patterns are linked to the movement of these temperatures by coastal wind patterns. Perch prefer areas with steep bathymetry, characterized by frontal activity due to interactions between the local bathymetry and tidal currents. Concerns that sampling only from highly successful commercial vessels may have biased abundance estimates, prompted the analysis of historical records of fish catch and government research surveys. Analyses between different boat sizes, different areas and different seasons from the original historical data base and a corrected subset revealed that it was mainly differences between areas that was responsible for the biasing of estimates. Deeper areas predictably produced more fish for all sizes of boats, but were fished more often by the larger boats used in the study. Therefore the field abundance estimates are likely to be biased towards areas of larger perch concentrations. / Science, Faculty of / Zoology, Department of / Graduate